The present disclosure relates to a developing device that forms a toner image by feeding magnetic toner toward an electrostatic latent image formed on a circumferential surface of a photosensitive drum by electrophotography and an image forming apparatus having the same, and particularly to a technique for suppressing turbulence of a toner layer at opposite ends of a developing sleeve.
In electrophotographic image forming apparatuses, a toner image is formed by feeding magnetic toner from a developing device toward an electrostatic latent image formed on a surface of a photosensitive drum. Such a developing device has a developing roller made up of a magnetic roller and a developing sleeve, forms a toner layer on a circumferential surface of the developing sleeve, and feeds the magnetic toner from the developing sleeve to the surface of the photosensitive drum. In order to prevent toner leakage when the magnetic toner on the circumferential surface of the developing sleeve moves to opposite ends of the developing sleeve in a rotation axis direction of the developing sleeve, technology for disposing seal members formed of a magnetic material at the opposite ends of the developing sleeve in the rotation axis direction of the developing sleeve in a non-contact way is known. Thereby, magnetic brushes are formed between the magnetic roller and the developing sleeve, and inhibit the magnetic toner on the circumferential surface of the developing sleeve from moving to the opposite ends of the developing sleeve in the rotation axis direction of the developing sleeve.